In high mobility samples, at charge neutrality, low temperature and for zero external fields, low energy bands have been observed to be gapped in bilayer graphene [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, Bernal multilayers with up to \(N=8\)  layers [7]}, [8]}, [9]}, rhombohedral multilayers with up to \(N=4\)  layers [10]}, [11]}, [12]} and recently with \(N \approx 12\)  [13]}. A number of different interaction-induced broken symmetry states have been proposed for bilayer graphene [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, [22]}, [23]}, [24]}, [25]}, [26]}, [27]}, [28]}, [29]} including pseudospin layer antiferromagnetic (AF) states [15]}, [19]}, [23]}, [24]}, [25]} in which electrons with different spin and valley flavors spontaneously accumulate on different layers, creating an odd parity state that breaks inversion symmetry and opens a gap. Owing to the antiferromagnetic configuration of four flavors, there is no net charge accumulation on summing over them and, thus, no cost in terms of Hartree energy.
The evolution of similar gapped states with layer number has been discussed for both Bernal [35]}, [36]} and rhombohedral multilayers [23]}, [38]}, [39]}, [40]}.
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